You're right, we can't. Instead it goes to dust and everyone loses.
I don't expect content to be more than a week old when it's in my feed but Ecency does that thing where they allow only the selfishest users on the block to sponsor for two weeks.
I'm not a fan of self sponsored content anyway. Says a lot about the author when the only sponsorships they've ever purchased are their own and none for the community. When they choose to sponsor beyond thay 7 day pay period, though, they really top the selfish meter.